Hundreds of abandoned cars were littered across local roadways and dozens of panicked motorists had to be rescued from submerged vehicles during an “unprecedented and unpredicted” storm that dumped a record-breaking amount of rainfall on Long Island, Suffolk County Executive Steve Bellone said.

Standing in front of the North Babylon Fire Department Wednesday afternoon, Bellone told reporters that the storm contributed to one death on the Long Island Expressway and left countless homes and streets flooded across the county.

“Unfortunately we’ve had another historic, extreme weather event,” he said, joined by firefighters who hours earlier waded through waist-high water on the Southern State Parkway to rescue drivers—some of whom were panicked—trapped in a sea of rainwater.

Bellone also announced that he declared a state of emergency at 8 a.m.

The epic storm swept across Long Island early Wednesday and dumped more than 13 inches of rain on Islip, and more than 10 inches in West Islip, Bay Shore and Holbrook.

Parts of Nassau County—Massapequa, Wantagh, Merrick—measured more than 6 inches of rain, but Suffolk appeared to have taken the brunt of the storm.

“When the big trucks went through, I followed,” said Marcos Mercado, a mechanic whose Mustang was stuck driving in floodwater on Union Boulevard in Islip for seven hours before he pushed it out and got it started. “I’m safe, that’s all that matters.”

The storm eclipsed a record for rainfall in one 24-hour period that was set in August 2011 during Tropical Storm Irene. That storm dropped 11.6 inches in upstate Tannersville. Islip measured 11.26 inches as of 9:30 a.m., the National Weather Service said.

The deluge came as a shock to first responders and local officials across Long Island.

Bellone called it “unprecedented and unpredicted,” several times, adding that “hundreds of vehicles [are] stranded on roadways across the county.”

“Hundred-year storms happen with regularity,” he said, referring to tropical storms and hurricanes, “this was a 500-year storm.”

Bellone was joined by Gov. Andrew Cuomo’s secretary Larry Schwartz, who is also a former chief deputy of Suffolk County. Cuomo is currently touring Israel, but Bellone still thanked the governor, who dispatched Schwartz to help with the recovery efforts.

“Gov. Cuomo is very aware of what’s going on,” Schwartz said. “We are bringing all state assets to bear.”

The state has 400 maintenance staff working in affected areas, pumping water from roadways and clearing debris carried by floodwaters from drainage gates and recharge basins. Crews are also assessing road damage, the governor’s office said.

The State Department of Environmental Conservation has also closed shellfish harvesting areas in most towns in Nassau and Suffolk counties as a precaution.

Bellone and Schwartz also thanked first responders for risking injury to rescue stranded motorists.

1030am: NO more flash flood warnings in effect. Flooding issues will continue until the water can recede. STAY SAFE! Only light rain left.

The North Babylon Fire Department deployed brush trucks, which were originally designed to battle brush fires, to access idle vehicles swallowed up by the record rainfall, said Bellone, adding that on the Southern State Parkway some cars were “actually floating down the highway.” In some areas, first responders also utilized rafts to reach drivers stuck on local roadways.

Lt. Tim Harrington of the North Babylon Fire Department described a harrowing scene at the Belmont Lake State Park exit along the Southern State Parkway.

When he arrived, he spotted some cars that were completely submerged or on the side of the road. Firefighters waded through a quarter-mile stretch of the highway and pulled people out of their vehicles, he said. Some were panicking.

“I’ve never seen anything like this before,” Harrington said, adding that upwards of 50 people were rescued.

“They did amazing job,” added Bellone.

Officials and forecasters said they were caught off-guard by the ferocious storm.

Bellone defended the county’s response.

“I wouldn’t say anything went wrong,” he said at the press conference in response to a reporter’s question. “This was an unprecedented and unpredicted event,” he reiterated, touting first responders’ “incredible response.”

In Islip, one of the hardest-hit areas, Supervisor Tom Croci urged residents to stay off all roadways as the town continues the recovery process.

“Town personnel and equipment have been dispatched and will work round-the clock to ensure the health, safety and welfare of our residents,” said Croci, who declared a state of emergency in the town.

Brookhaven Town Supervisor Ed Romaine warned residents that although rainwater has receded throughout the day, the ground in many areas was saturated and could potentially cause sinkholes, like this one in Bay Shore, collapse cesspools and uproot trees.

“In the wake of the historic rainfall we experienced this morning, I have declared a State of Emergency in the Town of Brookhaven,” Romaine said. “This unprecedented weather event has caused significant damage to a number of homes and buildings in our Town.”

State police also announced Wednesday afternoon that all Long Island parkways previously closed due to the storm are now open.

Cuomo’s office said a Department of Financial Services’ mobile command center would be set up Thursday from 8 a.m. to 8 p.m. at the Islip Town Hall parking lot located at 401 Main Street to provide insurance assistance to homeowners, renters, and businesses affected by the flooding.